I have this exact same issue, except my maximized window only leaves a gap of about an inch at the bottom of the screen. I have Windows XP.

The issue started when I bought the UltraPlusPAK - when I used the Pro installation there was no problem.

I haven't sought a cure because it doesn't bother me that much - I still have enough space. It is weird, though, since no other program has ever done that on my computer.